Modern internal combustion engines regularly comprise exhaust-gas turbochargers. An exhaust-gas turbocharger in principle comprises a turbine, which is disposed in an exhaust-gas tract of the internal combustion engine, and a compressor, which is disposed in an intake tract of the internal combustion engine and is mechanically coupled to the turbine. A rotational speed of the compressor, which may also be referred to as the turbocharger speed, may be controlled for example by means of a waste gate, which is disposed in a bypass around the turbine in the exhaust-gas tract.
The document DE 10 2005 007 558 A1 discloses a monitoring of at least one of the variables: increment rate, turbocharger speed and turbocharger speed for protecting a turbocharger connected to an engine from overspeeding in a vehicle having an exhaust-gas brake valve. Further disclosed is a closing of an exhaust-gas brake to reduce the speed of the turbocharger in each case as a response to the increment rate of the turbocharger speed being greater than or equal to a first limit value and the turbocharger speed being greater than or equal to a second limit value.
The document DE 10 2004 042 272 A1 discloses a controlling or controlling of the boost pressure of an internal combustion engine having a compressor in an air supply of the internal combustion engine, wherein an actuator is provided, by means of which the boost pressure of the compressor is adjusted. In dependence upon a rotational speed of the compressor an output signal for the actuator is determined.